Serum factors affecting choline uptake and incorporation in Schistosoma mansoni adults.

Uptake and incorporation of choline into adult Schistosoma mansoni was examined in the presence of serum from known permissive and non-permissive hosts. Uptake of choline was not significantly different for paired, male or female worms in any one treatment. The presence of serum from uninfected rat, hamster and human sources and from infected rat and hamster sources did not significantly affect choline uptake. Heat-inactivation of these sera before addition to the culture medium also had no effect on choline uptake. The incorporation of choline into phosphatidylcholine appeared similar in all of the sera until 30-min incubation at which point some significant differences could be demonstrated. Increased incorporation could be shown with the addition of serum from uninfected rat, hamster and human sources. Heat-inactivation of these sera abrogated this effect. The stimulation of choline incorporation into phosphatidylcholine is discussed in relation to the heat labile components of serum. Host permissiveness to infection did not alter choline uptake or incorporation into phosphatidylcholine.